There are many types of printing mechanisms. Different types of printing mechanisms are useful for different types of printing jobs. For example, inkjet printing is capable of producing high-quality color photographs from digital images. One type of inkjet printing mechanisms use cartridges, often called “pens,” which eject drops of liquid colorant, referred to generally herein as “ink,” onto a page. Each pen has a printhead formed with very small nozzles through which the ink drops are fired. To print an image, the printhead is propelled back and forth across the page, ejecting drops of ink in a desired pattern as it moves. The particular ink ejection mechanism within the printhead can include a piezo-electric or a thermal printhead mechanism. Other types of inkjet printers use individual pens rather than cartridges. Generally, four colors (black, cyan, magenta and yellow) need to be mixed to form an image. Problems can occur when one or more of the four colors becomes unavailable. One of the four colors can become unavailable for any number of reasons including simply running out of the color.
When colors become unavailable, consumable resources can be wasted. There are many consumable resources or consumables associated with printing a job. Ink, liquid toner or dry toner is one such resource. Inks, liquid toners or dry toners vary in cost. Another consumable resource or consumable is the media or paper on which a job is printed. The cost of printing media can be very little or can be in excess of $1.00 per sheet of media. Ordinary printing paper, for example, is inexpensive. However, special media can be used for printing high-quality photographs. The cost of photo-grade media can be very high.
Sometimes waste can occur due to the fact that printing is allowed to continue when doing so will waste a consumable or not accurately reflect a user's expectations. For example, when the ink or toner for one or more colors is in an insufficient supply, e.g. low or no yellow, the finished print job will have an appearance that will be unacceptable in view of what was anticipated. If the finished print job is unacceptable, then consumables such as ink and paper will have been consumed wastefully and the print process will have to be repeated.